But the honorable member sees great danger in the provision
concerning the militia. This I conceive to be an additional
security to our liberty, without diminishing the
power of the states in any considerable degree. It appears
to me so highly expedient that I should imagine it would
have found advocates even in the warmest friends of the
present system. The authority of training the militia, and
appointing the officers, is reserved to the states. Congress
ought to have the power to establish a uniform discipline
throughout the states, and to provide for the execution of
the laws, suppress insurrections, and repel invasions: these
are the only cases wherein they can interfere with the militia;
and the obvious necessity of their having power over
them in these cases must convince any reflecting mind.
Without uniformity of discipline, military bodies would be
incapable of action: without a general controlling power to
call forth the strength of the Union to repel invasions, the
country might be overrun and conquered by foreign enemies:
without such a power to suppress insurrections, our
liberties might be destroyed by domestic faction, and domestic
tyranny be established.

Elliot, Jonathan, ed. The Debates in the Several State Conventions on the Adoption of the Federal Constitution as Recommended by the General Convention at Philadelphia in 1787. . . . 5 vols. 2d ed. 1888. Reprint. New York: Burt Franklin, n.d.